Drafting instrument



Oct. 8, 1929. J. H. FISCHER 1,730,496

DRAFTINGINSTRUMENT Filed Feb. 192'! Patented Oct. 8, 1929 JOHN HENRY FISCHER, OF NEW YORK, N. Y., ASSIGNOR TO EAGLE PENCIL COMPANY,

OF NEW YORK, N. Y., A CORPORATION OF DELAWARE D'RAFTING INSTRUMENT Application filed February 1, 1927. Serial No. 165,061.

This invention relates generally to improvements in drafting instruments, and has particular reference to improvements in what are known as compasses and dividers.

One object of the invention is to provide a novel construction by which a lead may be mechanically fed as the lead is consumed.

Another object of the invent-ion is to provide a construction whereby the lead carry? ing and feeding mechanism may be reversed in one leg of a pair of compasses to expose for use a pointed pm for engaging the paper or other material when it 1s deslred to use a drawing pen on the other leg of the comnected in such away as to limit them normally to a relative rotary movement.

With the foregoing and other objects in view, the invention consists in a novel con struction and combination of parts, the novel features of which are pointed out in appended claims, and a preferred embodiment of which is hereinafter described with reference to the drawing accompanying andforming a part of this specification.

In said drawing Fig. 1 shows a pair of compasses and dividers of a well known type with the invention applied thereto.

Fig. 2 is a longitudinal section through the detachable device which contains the new features of the construction.

Fig. 3 is an elevation of the device shown in section in Fig. 2.

Fig. 4 shows the detachable device dis-assembled partially to show certain details of the construction. v j V The device shown in the drawing comprises a pair of legs 10 and 11 pivotally connected at 12 and held in the different angular positions to which they may be adjusted in any desired way. The legs 10 and 11 are formed from material having a certain amount of resiliency and are split or left with theadj acent edges of the'metal unattached as at 13 to form a clutch at the lower end of each leg. 7

One of the legs carries an element 14 provided with a socket or clip to hold an inserted pen 15 and carries a pin 16 for engaging the paper or corresponding drafting material.

The other leg of the compasses carries the lead feeding mechanism and associated parts. These comprise a shell 17 of any suitable material having an end shaped as at 18. Se

cured within the portion 18 of the shell'17 is a split tube 19 into which lead or other marking material 20 may be inserted. This split tube projects beyond the portion 18 o-f the shell 17 and at its end 22 isrestricted sufii-' ciently to frictionally engage the lead 20.

Cooperating with the shell 17 is a shell 28 having an external diameter suficient for the shell 23 to have a snug fitwithin the open end of. the shell 17. In order to permit easy assembling and normally limit relative movement of the two shells to a rotary movement the shell 237is provided with a peripheral groove 24 and the shell 17 with internal short ribs or projections 25 formed by inwardly indenting the material of the shell. In as sembling the two shells are telescoped until the ribs25 snap into the groove 24, movement past the point where the ribs and groove engage being prevented as hereinafter made clear. This construction permits employing the resiliency of the material of the two shells to effect the connection and permits disengage 7 ing the two sections of the shell without damage to either if it is desired to their, interiors for any purpose.

Secured within the portion 26 of the shell 23 is what is for convenience referred to here in as the helix. This helix, designated 27 in the drawing is of any suitable material formed as shown at 28'to construct an intergain access to nal thread lightly contacting the periphery of the split tube 19 when the parts are in assembled relation.

is a propeller rod 29 provided with projectlons 3O extendingthrough the slot in the split tube into engagement with the internal Slidably supported within the split tube threads 28 of the helix. It is apparent that relative rotations of the shells 17 and 23 will cause the propeller rod 29 to advance or retract, the direction of movement of the rod depending upon the direction ofthe relative rotation. The split tube 19 is of such length that in assembling the parts the end 32 of the tube will engage the inner wall of the portion 83 of the shell 23, thereby preventing the ribs 25 riding past the groove 24: when the shells are being fitted together. I

The portion 33 of the shell 23 is provided with an axially extending opening 84 and soldered or otherwise fastened to the split tube 19 is a pin 35 which is pointed at its free end as shown at 36. hen the parts are inthe1r normal assembled relation the pin 35'. extends through the opening 34, theconst-ruction being such that the pin is limited to a rotary movement in the open ng. It is obvious that this cooperation of the pin and opening provides a bearing support for the unattached end or the split tube 19 and that the tube will in turnaiiord a bearing and support for the unattached portion of the .helix 27. This construction and arrangeporting and maintainingthe parts in correct} ment of the parts is a desirable one, particularly in a construction where the parts are all small in dimensions and made of material which is not highly resistant to damage In addition to the advantages in the way of suprelations, the pin is available for use in the usual way either in connection with the pin 16 or the drawing pen 15'.

In order to facilitate operation to feed the lead, the shell 23 is provided with a knurled.

band or bead 40 of sufiicient diameter to give a firm frlctlonal engagement with the lnterlor of the clutch portion at the lower end of the.

7 leg of the comp asses, thereby preventing rotation of the unit as a whole when an attempt is made to feed the lead by turning the shell ics;

7 limited to details except as they in the following claims.

VVh-at is claimed is: 1. In a device of the character described, a pair'o'f shells connected for relative rotation and provided with axial openings in their non-adjacent ends, a lead feeding mechanism within the shells constructed to feed lead in one of said openings'by relative rotations' of the shells, said mechanism comprising a split tube secured within one of said shells, and a ,pin integral with thesplit tube and projecting through the other of said openings.

2. In a device of the character described,

the combination of a pair of shells connected for relative rotation and provided with axial openings. at their non-adjacent ends, lead feeding mechanism for feeding lead through i one of said openings comprismg ja spht tube secured within one of said shells and a helix surroundingthe split tube and secured within the other of said shells, and a pin rigid with the split tube and extending through the other of said openings to form a bearing support for the split tube and having the exposed end of thepin pointed.

3. In a device of the character described, a pair of shells, one of which has a sliding fit within the other, there being a peripheral groove in the inner shell, and a plurality of short internally projecting ribs carried by 'the outer shell and engaging in the aforesaid peripheral groove.

'4. Ina device of the character described, a lead feeding mechanism, a casing for the lead feeding mechanism comprising a pair of shells, one of which has a rotating fit within the c'ther,'there being a peripheral groove in one of the shells, and a plurality of short ribs on the other shell engaging said groove,

said ribs and groove cooperating normally to l mit the shells to a rotary relative movement.

5. A reversible plug for use in a leg of a pair of compasses comprising two shells connected for relatlve rotation, lead feeding mechanism within said shells and connected".

for operation by relative rotation of the shells to feed lead through an opening in the end'of oneofthe'shel'ls, and a pin projecting outward from the 'endot the other shell. p 1 I In testimony whereof'I hereto affix my signature. v I

JOI-INI-IENRY FISCHER. 

